<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <div id="app">
        {{message}}
        <div v-if="text=='A'">
            text:A
        </div>
        <div v-else-if="text=='B'">
            text:B
        </div>
        <div v-else="text=='C'">
            text:C
        </div>
        <span>{{b}}</span>
    </div>
    <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
    <script>
        var vm=new Vue({
            el:'#app',
            data:{
                message:'hello word',
                ok:true,
                text:'A',
            }
        })
        vm.b="测试";
        //表示阻止修改现有属性
        Object.freeze(vm);
        alert(vm.b);
    </script>
</body>
</html>